The present disclosure describes technologies relating generally to assignment of network addresses, and more specifically to hierarchical address assignment in mobile, wireless ad hoc networks.
Two or more mobile devices can communicate with each other as wireless clients of a wireless network. Examples of such mobile devices are laptop or tablet computers, smartphones, personal digital assistants (PDAs), digital cameras, child monitoring devices, and the like. A wireless network is said to operate in infrastructure mode if communications of the two or more wireless clients are bridged through a wireless access point. The wireless network is said to operate in ad hoc mode if the two or more mobile devices communicate with each other directly, without the use of a wireless access point. The ad hoc mode is also commonly referred to as a wireless peer-to-peer (P2P) mode. Wireless clients in ad hoc mode form an independent basic service set (IBSS). In this specification, a wireless network operating in ad hoc mode and including mobile devices is referred to, interchangeably, as an ad hoc network, an IBSS network, or a wireless P2P network.
In some IBSS networks, one of the wireless clients, e.g., a mobile device that was the first wireless member in a given IBSS network, can periodically beacon to identify the given IBSS network, and can authenticate new members. Hence, this wireless client acts as a Dynamic Host Configuration Protocol (DHCP) server that assigns addresses to the new members, such that the assigned addresses are not conflicting. To join the given IBSS network, a mobile device would locate the wireless client that acts as the DHCP server to obtain an address on the given IBSS network.
In other IBSS networks known as zero configuration networks, to join the network a mobile device selects a candidate address, e.g., an address within a reserved range of addresses, and uses Address Resolution Protocol (ARP) probes to ascertain that the candidate address is not in use on the network. The addressing approach used in zero configuration networks is referred to as link-local addressing, and requires multicast transmissions that should, ideally, reach all members of the IBSS network. Should a mobile device joining a zero configuration network determine that a selected candidate address is already in use within the zero configuration network, a new candidate address is selected by the mobile device.